The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.
Security screening may be desirable and may be conducted in many contexts. Sensors for detecting particulates and/or gases in the air may be useful, but are not in-of-themselves adequate.